Post 5 year review - negotiating full and final settlement

curlyK

Hi,
We have recently had our five year review and having contacted our mortgage provider and been refused any further lending, the IVA company have agreed to extend our arrangement for an additional 12 months (from next February when year 5 ends).
In the meantime my parents have offered to pay a full and final for us. My question is how much I should offer. Our agreement is for £280 per month, to finish this existing year and the additional 12 months at this rate would cost £4760. How much should I offer as full and final as my parents can't really afford this amount?
Any ideas? I would like to be realistic but not take any more from my parents than absolutely necessary.
Thanks for any help offered.